WA police on bikes catch more than 700

A P-PLATER taking selfies with a woman in his car and a motorcyclist with a child on a petrol tank are among 737 people caught by WA police on unmarked motorcycles since they were introduced last month.

The unmarked bikes were introduced as a trial over the festive season to target people using their mobile phones while driving.

But WA Police Commissioner Karl O'Callaghan said people were also caught for other "ludicrous" behaviour.

"We stopped a young mother travelling at more than 100km/h on the freeway," he told Fairfax radio on Thursday.

"She was texting on her mobile phone, she had a small child in the back with no booster seat and she was watched by the unmarked motorcyclist for about two kilometres.

"When she was eventually pulled over, she said 'I was just turning my mobile phone off' so she was taking two kilometres to do that."

Mr O'Callaghan said the P-plater taking selfies had lost his licence, which was a "good outcome".

No decision had been made yet on whether to continue using officers on unmarked motorcycles, Mr O'Callaghan said.

A NOTE ABOUT RELEVANT ADVERTISING: We collect information about the content (including ads) you use across this site and use it to make both advertising and content more relevant to you on our network and other sites.